Purpose of "seal wells" in an aqueduct?

[TexasCHe]

I recently took partial responsibility of an aging water pipeline that moves water several miles through hilly terrain. As the water moves up grade through a 36-inch pipe it has air/vacuum vents. As it crests over the top of the last hill and starts down grade to a lake. Just after this crest it enters what the older draws refer to as a “seal well” that’s basically an open air trough. The water passes through this trough and enters a 48-inch pipe that gravity flows the rest of the way to the pond. My question is what is the purpose of this “seal well”? None of the older information that’s available to me includes this information. It’s difficult to secure maintenance money if you don’t have a good description of what you’re attempting to maintain!

 

[rconner]

I am just curious as to what is the original source of the water the aqueduct carries, and is the lake just a water reservoir, or does it have any recreational etc. uses?

 

[TexasCHe]

A river serves as the source and pond that it flow into has no recreational use.

 

[bimr]

Don't completely understand your system, but would guess that the purpose of the seal well is to protect the pipe from collapse.

If you have the water moving down the hill, you may pull a vacuum on the pipe and collapse the pipe.

Sometimes it is less expensive to use thinner wall pipe than to design the piping for the maximum pressures that will occur.

 

[Artisi]

I would agree with "bimr" seeing as we don't have any further detail. Seems it is to stop any syphon effect and the problems that can be associated.

 

[BigInch]

In addition to the above, it "seals" the upstream pipeline, since any dewatering of those segments below trough level is prevented as well as backflow from the exiting reservoir to the upstream pipeline via reverse siphoning is also prevented.

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